{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://jetlumen.com/ordo/schema/process-definition.json",
  "title": "Ordo process definition document",
  "$comment": "Document shape for ProcessDefinitionParser.fromJson. Graph connectivity, unique ids, PARALLEL membership, due.goto branch rules, and predicate depth/leaf limits are enforced only by the parser.",
  "type": "object",
  "additionalProperties": false,
  "required": ["id", "name", "steps", "transitions"],
  "properties": {
    "id": { "$ref": "#/$defs/nonEmptyString" },
    "name": { "$ref": "#/$defs/nonEmptyString" },
    "version": {
      "type": "integer",
      "minimum": 0,
      "$comment": "Ignored by fromJson; written by toJson after publish."
    },
    "startStep": { "$ref": "#/$defs/nonEmptyString" },
    "steps": {
      "type": "array",
      "minItems": 1,
      "items": { "$ref": "#/$defs/topStep" }
    },
    "transitions": {
      "type": "array",
      "minItems": 1,
      "items": { "$ref": "#/$defs/transition" }
    }
  },
  "$defs": {
    "nonEmptyString": {
      "type": "string",
      "pattern": ".*\\S.*"
    },
    "literal": {
      "type": ["string", "number", "boolean"]
    },
    "topStep": {
      "oneOf": [
        { "$ref": "#/$defs/approvalStep" },
        { "$ref": "#/$defs/actionStep" },
        { "$ref": "#/$defs/parallelStep" }
      ]
    },
    "leafStep": {
      "oneOf": [
        { "$ref": "#/$defs/approvalStep" },
        { "$ref": "#/$defs/actionStep" }
      ]
    },
    "approvalStep": {
      "type": "object",
      "additionalProperties": false,
      "required": ["id", "name", "candidates"],
      "properties": {
        "id": { "$ref": "#/$defs/nonEmptyString" },
        "name": { "$ref": "#/$defs/nonEmptyString" },
        "kind": { "const": "APPROVAL" },
        "candidates": {
          "type": "array",
          "minItems": 1,
          "uniqueItems": true,
          "items": { "$ref": "#/$defs/nonEmptyString" }
        },
        "policy": { "type": "string", "enum": ["ANY", "ALL"] },
        "due": { "$ref": "#/$defs/due" }
      }
    },
    "actionStep": {
      "type": "object",
      "additionalProperties": false,
      "required": ["id", "name", "kind", "action"],
      "properties": {
        "id": { "$ref": "#/$defs/nonEmptyString" },
        "name": { "$ref": "#/$defs/nonEmptyString" },
        "kind": { "const": "ACTION" },
        "action": { "$ref": "#/$defs/nonEmptyString" },
        "policy": { "type": "string", "enum": ["ANY", "ALL"] }
      }
    },
    "parallelStep": {
      "type": "object",
      "additionalProperties": false,
      "required": ["id", "name", "kind", "branches"],
      "properties": {
        "id": { "$ref": "#/$defs/nonEmptyString" },
        "name": { "$ref": "#/$defs/nonEmptyString" },
        "kind": { "const": "PARALLEL" },
        "policy": { "type": "string", "enum": ["ANY", "ALL"] },
        "branches": {
          "type": "array",
          "minItems": 2,
          "items": { "$ref": "#/$defs/branch" }
        }
      }
    },
    "branch": {
      "type": "object",
      "additionalProperties": false,
      "required": ["id", "steps", "transitions"],
      "properties": {
        "id": { "$ref": "#/$defs/nonEmptyString" },
        "steps": {
          "type": "array",
          "minItems": 1,
          "items": { "$ref": "#/$defs/leafStep" }
        },
        "transitions": {
          "type": "array",
          "minItems": 1,
          "items": { "$ref": "#/$defs/transition" }
        }
      }
    },
    "due": {
      "oneOf": [
        {
          "type": "object",
          "additionalProperties": false,
          "required": ["after", "then", "to"],
          "properties": {
            "after": { "$ref": "#/$defs/isoDuration" },
            "then": { "const": "reassign" },
            "to": { "$ref": "#/$defs/nonEmptyString" }
          }
        },
        {
          "type": "object",
          "additionalProperties": false,
          "required": ["after", "then"],
          "properties": {
            "after": { "$ref": "#/$defs/isoDuration" },
            "then": { "const": "notify" },
            "action": { "$ref": "#/$defs/nonEmptyString" }
          }
        },
        {
          "type": "object",
          "additionalProperties": false,
          "required": ["after", "then", "to"],
          "properties": {
            "after": { "$ref": "#/$defs/isoDuration" },
            "then": { "const": "goto" },
            "to": { "$ref": "#/$defs/nonEmptyString" }
          }
        }
      ]
    },
    "isoDuration": {
      "type": "string",
      "minLength": 2,
      "$comment": "java.time.Duration.parse; must be positive after parse."
    },
    "transition": {
      "type": "object",
      "additionalProperties": false,
      "required": ["from"],
      "properties": {
        "from": { "$ref": "#/$defs/nonEmptyString" },
        "to": {
          "type": ["string", "null"],
          "minLength": 1
        },
        "when": { "$ref": "#/$defs/when" },
        "priority": { "type": "integer" }
      }
    },
    "when": {
      "oneOf": [
        { "$ref": "#/$defs/refWhen" },
        { "$ref": "#/$defs/predicate" }
      ]
    },
    "refWhen": {
      "type": "object",
      "additionalProperties": false,
      "required": ["ref"],
      "properties": {
        "ref": { "$ref": "#/$defs/nonEmptyString" },
        "args": {
          "type": "object",
          "additionalProperties": true
        }
      }
    },
    "predicate": {
      "oneOf": [
        { "$ref": "#/$defs/compareEq" },
        { "$ref": "#/$defs/compareNe" },
        { "$ref": "#/$defs/compareGt" },
        { "$ref": "#/$defs/compareGte" },
        { "$ref": "#/$defs/compareLt" },
        { "$ref": "#/$defs/compareLte" },
        { "$ref": "#/$defs/inPredicate" },
        { "$ref": "#/$defs/andPredicate" },
        { "$ref": "#/$defs/orPredicate" },
        { "$ref": "#/$defs/notPredicate" }
      ]
    },
    "comparePair": {
      "type": "array",
      "minItems": 2,
      "maxItems": 2,
      "prefixItems": [
        { "$ref": "#/$defs/nonEmptyString" },
        { "$ref": "#/$defs/literal" }
      ]
    },
    "compareEq": {
      "type": "object",
      "additionalProperties": false,
      "required": ["eq"],
      "properties": { "eq": { "$ref": "#/$defs/comparePair" } }
    },
    "compareNe": {
      "type": "object",
      "additionalProperties": false,
      "required": ["ne"],
      "properties": { "ne": { "$ref": "#/$defs/comparePair" } }
    },
    "compareGt": {
      "type": "object",
      "additionalProperties": false,
      "required": ["gt"],
      "properties": { "gt": { "$ref": "#/$defs/comparePair" } }
    },
    "compareGte": {
      "type": "object",
      "additionalProperties": false,
      "required": ["gte"],
      "properties": { "gte": { "$ref": "#/$defs/comparePair" } }
    },
    "compareLt": {
      "type": "object",
      "additionalProperties": false,
      "required": ["lt"],
      "properties": { "lt": { "$ref": "#/$defs/comparePair" } }
    },
    "compareLte": {
      "type": "object",
      "additionalProperties": false,
      "required": ["lte"],
      "properties": { "lte": { "$ref": "#/$defs/comparePair" } }
    },
    "inPredicate": {
      "type": "object",
      "additionalProperties": false,
      "required": ["in"],
      "properties": {
        "in": {
          "type": "array",
          "minItems": 2,
          "maxItems": 2,
          "prefixItems": [
            { "$ref": "#/$defs/nonEmptyString" },
            {
              "type": "array",
              "minItems": 1,
              "items": { "$ref": "#/$defs/literal" }
            }
          ]
        }
      }
    },
    "andPredicate": {
      "type": "object",
      "additionalProperties": false,
      "required": ["and"],
      "properties": {
        "and": {
          "type": "array",
          "minItems": 1,
          "items": { "$ref": "#/$defs/predicate" }
        }
      }
    },
    "orPredicate": {
      "type": "object",
      "additionalProperties": false,
      "required": ["or"],
      "properties": {
        "or": {
          "type": "array",
          "minItems": 1,
          "items": { "$ref": "#/$defs/predicate" }
        }
      }
    },
    "notPredicate": {
      "type": "object",
      "additionalProperties": false,
      "required": ["not"],
      "properties": {
        "not": { "$ref": "#/$defs/predicate" }
      }
    }
  }
}